Divisible laminated magnetic core structures for transformers or choke coils of great power



E. A. FROWEIN 3, 546,645

T POWERFO Dec. 8., 1970 DIVISIBLE LAMINATED MAGNETIC CORE STRUCTURES TRANSFORMERS OR CHOKE COILS OF GREA Filed Dec. 17, 1968 PIC-3.2

INVENTOR fqzsfirusAfkawflN United States Patent 3,546,645 DIVISIBLE LAMINATED MAGNETIC CORE STRUC- TURES FOR TRANSFORMERS OR CHOKE COILS OF GREAT POWER Egbertus A. Frowein, Arnhem,

Smit Nijmegen Electrotechnische Fabriken N.V., Nijmegen, Netherlands, a company of the Netherlands Filed Dec. 17, 1968, Ser. No. 784,416 Claims priority, application Netherlands, Dec. 21, 1967, 6717462 Int. Cl. H01f 27/08, 27/24 US. Cl. 336-60 Netherlands, assignor to 4 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a divisible laminated magnetic core structure for a transformer or a choke coil of great power, said core structure consisting of parts which are interconnected by strip-shaped coupling laminations of equal widths and facing each other, while there is left between them at the most a narrow gap, with laminations protruding towards one another and lying in the same layers of the core, said coupling laminations being clamped on the one hand between protruding laminations of one of two interconnected core parts and on the other hand between protruding laminations of the other one of said two core parts.

In the parallel Dutch patent application 67.00909 of the Jan. 20, 1967 a divisible laminated magnetic core structure of this construction has been described, in which, as in known divisible magnetic core structures, the planes of separation between the core parts lie in the yoke portions of the core structure.

The invention has the object to use the fact that in the divisible magnetic core structure of the construction described hereabove relatively very narrow coupling laminations can be used, so that for the division of the core structure one is not restricted to the relativel large spaces in the yokes left between the windings. It consists in that the planes of division between said core parts extend in the leg portions of the magnetic core structure in places between the windings mounted on said leg portions and the yoke portions of said core structure. This way of dividing the magnetic core structure has the advantages that the places of division are readily accessible and there is no need to leave, during the coupling operation, spaces below the lower yoke portion and above the upper yoke portion to be able to insert the coupling laminations. Moreover, the core parts are easily manageable and transportable, since they have more favourable shapes and, as to the leg portions with the windings, are considerably shorter, whereas on the spot, where the transformer or the choke coil is to be erected, the windings can be mounted on the leg portions of the core structure, so that the leg portions and the windings may be transported separately, if desired. Finally, the assembled magnetic core structure forms mechanically a stronger unit, as the yoke portions can be made in the usual way as one whole.

The invention will be elucidated wth the aid of the drawing. In the drawing is:

FIG. 1 an elevational view of the upper part of a three phase transformer provided with a divisible magnetic core structure according to the invention.

FIG. 2 is a cross sectional view taken on the line IIII in FIG. 1.

FIG. 3 on a larger scale a cross sectional view of portions of two core parts to be coupled, in which for the sake of clearness the normally only 0.3 mm. thick laminations are made too thick in the drawing, and

FIG. 4 an elevational view of a layer of laminations of the portion shown in FIG. 3 of the core parts interconnected by coupling laminations.

In the drawing 1 is the yoke portion and 2 are the leg portions of a laminated magnetic core structure of a three phase transformer, said core structure being divisible at 3. This yoke portion 1 and these leg portions 2 are interconnected by coupling laminations 4, 4'. Also FIG. 2 shows some of these coupling laminations. The leg portions 2 are each provided with a cooling gap 5 and they carry each a winding 6.

It appears from FIGS. 3 and 4 that parts 1, 2 of the laminated magnetic core structure to be interconnected are provided with laminations 7, 8 protruding towards each other and lying in the same layers and that said core parts are spaced apart by a narrow gap 9. Therein the coupling laminations are slid into the spaces left between the protruding laminations 7, 8. Since the leg portions 2 are each provided with a cooling gap 5, each leg portion is connected with the yoke portion 1 by two groups of coupling laminations 4, 4'.

The coupling laminations 4, 4' are narrow strips having a width of 3-4 cm., so that they are readily inserted in the spaces left between the ends of the winding 6 and the yoke portion 1, since these spaces are normally considerably wider, for instance 8 cm. wide.

What I claim is:

1. A transformer or like assembly adapted for the separate transportation of component parts thereof and the erection and assembly of such component parts at an .installation site, comprising in combination,

a laminated magnetic core assembly including a pair of substantially parallel elongate leg portions and a pair of substantially parallel yoke portions, each yoke portion extending laterally from a corresponding end of one of said leg portions to terminate at its opposite end in close proximity to a corresponding end of the other leg portion whereby said other leg portion may be fitted between said yoke portions at the installation site, each such opposite end and the corresponding ends of said other leg portion having alternate laminations thereof recessed to provide slots, the slots in said opposite ends of said yoke portions and the slots in the ends of said other leg portion being coplanar and a plurality of coupling laminations filling said slots and bridging between said other leg portion and said yoke portion to close the magnetic path of said core assembly; and,

a winding supported on said other leg portion, said winding being of an axial length which is less than the length of said other leg portion to expose end portions of said other leg portion which are slightly greater in length than the depths of said slots;

said end portions of the other leg portion each having a transverse notch dividing such end portions beyond said winding.

2. The transformer or like assembly as defined in claim 1, wherein the slotted ends of said yoke portions are laterally offset from said yoke portions in coaxial relations to said other leg portion, the lateral offset of each such slotted end being of greater length than the depths of said slots, each such slotted end having a transverse notch dividing such slotted end to a depth greater than the depths of said slots, the notches in said other leg portion and said notches in said yoke portions being aligned and there being two sets of coupling laminations at each end of said other leg portion filling the divided slots with the corresponding ends of such two sets being spaced apart to communicate the aligned notches.

3. The transformer or like assembly as defined in claim 2, wherein said one leg portion is formed separate from said yoke portions and similarly to said other leg portion, the yoke portions being joined to both leg portions by coupling laminations, and there being a second winding on said one leg portion.

4. The transformer or like assembly as defined in claim 1, wherein said one leg portion is formed separate from said yoke portions and similarly to said other leg portion,

References Cited UNITED STATES PATENTS 2,523,072 9/1950 Somerville 336216X 2,702,936 3/1955 Hunt 336211X 3,344,383 9/1967 Aberizk 336-217X THOMAS J. KOZMA, Primary Examiner US. Cl. X.R. 

